In recent years, such wheelchairs have been developed as self-running type of wheelchairs provided with an electric motor operated by a rider using a joystick, and electric motor-assisted type of wheelchairs in which the rider's physical force applied to the handle rims is detected and assisted with an electric driving motor.
Nursing type of wheelchairs pushed by a nursing person from behind has also been conventionally used. A type of wheelchair has also been proposed in which the above-mentioned nursing type of wheelchair is provided with an electric motor, and the operational force applied by the nursing person to the nursing-purpose handle is detected to output assisting power commensurate with the operational force (JP-A-6-304207).
In the above-described nursing type of wheelchair, the operational force detection and the drive are performed independently on right and left wheels. Therefore, it requires plural sensors and so is disadvantageous in costs. Moreover, since the operational force is detected independently on right and left sides, the nursing person is obliged to use both hands for operation. Also, since the wheelchair cannot move straight unless the operational force is applied equally to right and left sides, awkwardness might be felt in operation. Therefore, much care is required in operation and so burden on the nursing person is a concern.
The conventional nursing type of motor-assisted wheelchair above is constituted such that the operational force is detected also in the pulling back direction of the handle to provide assisting power in the reverse direction. Therefore, when the nursing person operates the wheelchair with the front wheels lifted to negotiate a step in the so-called wheelie operation, the operational force similar to that for the reverse movement is undesirably applied and ends up in the reverse rotation of the motor. That is a problem of poor ease of operation.
The same problem of the poor ease of operation is experienced with the conventional nursing type of motor-operated wheelchair: Since a push-handle is attached to the wheelchair through a detecting section for moving the wheelchair back and forth, the operational force applied to the push-handle is detected also when the force is applied in the reverse direction to provide assisting power in the reverse direction. Therefore, when the nursing person operates the wheelchair with the front wheels lifted to negotiate a step in the so-called wheelie operation, the operational force for the reverse movement is undesirably applied and ends up in the reverse rotation of the motor.
The present invention has been made in view of the above problems to provide a nursing type of motor-operated wheelchair capable of improving ease of operation.